Did Baumgartner Boom?

After Felix Baumgartner's skydive from 24 miles created such a stir on Sunday, I was curious about something, so I asked my scientist friend Phil Plait:

In exceeding the speed of sound, did Baumgartner create a sonic boom? If so, did he hear it? Did anyone else hear it? Does size matter (e.g. human vs plane) in creating the boom?

Phil replied: "He'd create a shock wave, but wouldn't hear it since he'd be moving faster than the sound of it trying to catch up to him! Size does matter, but also how high he was when he broke the sound barrier. If he was too high up, then it would dissipate."